Sycamore plant named ‘DRABROT’

ABSTRACT

A new variety of  Platanus occidentalis  named ‘DRABROT’ which is characterized by a contorted, semi-weeping branch habit and dark green, disease-free leaves. In combination, these characteristics distinguish ‘DRABROT’ from all other cultivars known to the inventors.

Genus: Platanus.

Species: occidentalis.

Denomination: ‘DRABROT’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Platanusoccidentalis (American Sycamore or American Planetree) which is grown asa large ornamental tree for use in parks and landscape. The new cultivaris known botanically as Platanus occidentalis and will be referred tohereinafter by the cultivar name ‘DRABROT’.

The ‘DRABROT’ variety was found by Thomas M. Draves, an ISA CertifiedArborist, as a free-standing specimen tree incorporated into thelandscape of a residence in Darien, N.Y. and was recognized by him asunique for its contorted habit and semi-weeping branches. There is noevidence of ‘DRABROT’ arising as a mutation from any known form ofPlatanus, and therefore it is assumed to be a seedling of Platanusoccidentalis, planted in its current location at least 60 years ago.

The ‘DRABROT’ variety is the only variant of American Sycamore we areaware of that displays this form when compared to the followingcommercial selections: Platanus occidentalis ‘Yellow Sycamore’ U.S.Plant Pat. No. 5,359 with an arboreal form typical of the species butslower growth and yellow leaves; Platanus occidentalis ‘Grenickle’ (notpatented) SILVERWOOD™ Sycamore, with both height and width reaching75-100′, bark white. The majority of commercially produced Platanus areforms of the hybrid Platanus x acerifolia (Platanus occidentalis xPlatanus orientalis) , commonly known as London Planetree, none of whichhave the unique form of the ‘DRABROT’ selection, and as noted in TheTree Book, by Dirr & Warren, Timber Press 2019, are represented by thefollowing four, non-patented cultivars: Platanus x acerifolia‘Bloodgood’ (70′ tall×50′ wide); Platanus x acerifolia ‘Columbia’ (70′tall×50′ wide, USDA hardiness zone 6), Platanus x acerifolia ‘MortonCircle’ (EXCLAMATION!™ London Planetree) (60′ tall×30′ wide); andPlatanus x acerifolia ‘Suttneri’ (60′ tall×45′ wide, white and greenvariegated leaves, bark almost pure white).

The original tree is approximately 35′ tall by 48′ wide, and hasdeveloped two separate trunks with diameters of 10″ and 12″. Although wehave reproduced ‘DRABROT’ with two or more primary stems, mostcommercial applications utilize trees with only one, therefore, ourobservations and illustrations for the purpose of this declaration havefocused on trees with one trunk. Specifically, the oldest plantavailable to us, produced from the original, is a 17-year oldsingle-stem specimen in [The Draves Arboretum] an arboretum, currentlymeasuring 16′ tall×21′ wide, and that has a diameter of 6″ at a point12″ above the ground.

ASEXUAL PROPAGATION OF THE INVENTION

‘DRABROT’ was first asexually propagated by Tim Brotzman, co-inventor,in summer of 2003 in Madison, Ohio. Asexual propagation has beenaccomplished using softwood cuttings and by budding onto seedlingrootstock of Platanus occidentalis (not patented). Since that time,under careful observation, the distinguishing characteristics of‘DRABROT’ have been determined stable and uniform, and to reproduce trueto type in successive generations of asexual propagation.

DESCRIPTION OF THE INVENTION

Using observations collected from 17-year-old trees growing at[Brotzman's Nursery, Inc.] a nursery in Madison, Ohio and at [The DravesArboretum] an arboretum in Darien, N.Y., as well as the mother tree, wehave identified traits which in combination set ‘DRABROT’ apart from allother existing varieties of Platanus known to the inventors. ‘DRABROT’has not been tested under all possible conditions and phenotypicdifferences may be observed with variations in environmental, climatic,and cultural conditions. The distinguishing characteristics of ‘DRABROT’are as follows:

-   -   1. ‘DRABROT’ exhibits a contorted, semi-weeping branch habit.    -   2. ‘DRABROT’ lacks strong apical dominance    -   3. The leaves of ‘DRABROT’ are dark green and deciduous.    -   4. The leaves of ‘DRABROT’ have shown high degree of resistance        to Leaf Anthracnose (Apiognomonia veneta) and Powdery Mildew        (Erysiphe platani) in both Madison, Ohio and Darien, N.Y.    -   5. When grown as a single stem tree ‘DRABROT’ probably has a        mature height and width of less than 35′×40′.    -   6. The mature trunk of ‘DRABROT’ has exfoliating bark, revealing        a broken pattern of green-grayed-white colored patches.    -   7. ‘DRABROT’ is hardy at least to USDA Zone 5B.

BOTANICAL DESCRIPTION

-   Note: All references to color are using The R.H.S. Colour Chart,    published by The Royal Horticultural Society, London, England 1966.-   Parentage: Originated as a spontaneous seedling of American    Sycamore, Platanus occidentalis.-   Hardiness: USDA Hardiness Zone 5b.-   Growth rate: Slow compared to the specie and hybrids. When    propagated by chip budding, 1-yr whips of ‘DRABROT’ averaged 44.2″    in height and 0.313″ diameter, compared to Platanus x acerifolia    ‘Morton Circle’ which averaged 72.4″ and 0.813″ at the same age.    Three-year old ‘DRABROT’ exhibited the following averages: 27″    annual lateral branch length; 0.25″ lateral branch diameter;    3.0-3.5″ internodal spacing; 33″ annual vertical growth; overall    total plant height of 114″ and diameter of 1.35″ when measured 6″    above the ground. This compares to three-year-old Platanus    occidentalis with averages of: 36″ annual lateral growth; 0.225″    lateral branch diameter; 4.0-4.5″ internodal spacing; 72″ vertical    growth; overall plant height of 192″ and diameter of 2.55″ under    field conditions in Madison, Ohio.-   Form/branch habit: From a short central stem, rather than producing    a dominant central leader, multiple primary branches randomly arch    outward radially at angles of 35° to 70° (degrees) from vertical. As    these branches elongate, they contort and the tips may flatten    horizontally or droop as much as 120° to 160° from vertical,    yielding an umbrella-shaped crown with an interwoven, dense,    semi-weeping habit, the combination of which might make this    selection slightly more vulnerable to snow and ice load than is    typical of this specie.-   Bark: The bark on the trunk of young trees is smooth, tight and    dark, (Greyed-Green Group 195-A), with age developing lighter    colored exfoliating plates (Greyed-Green Group 195-C to Greyed-Green    Group 195-A) until finally on old plants nearly all white (White    Group 155-C).-   Leaves: Deciduous. Arranged alternately on stems, simple, with 3-5    lobes and toothed margins, palmate venation. Thick, generally tatter    resistant leaf blade to 8 inches or more wide and 6-7 inches long,    held horizontally to slightly pendant. Tip is acute, base of older    leaves typically cuneate. Newly emerged and young leaves, until    reaching full size, have an unusual basal flap for which there is    not a recognized, specific taxonomic term. Proportional to the size    of the leaf and up to 1″ wide and 0.5″ long and not attached to the    petiole, unlobed, auriculate and moderately toothed perhaps best    described as a modified blade stipule or irregular peltation. As the    leaf matures this feature disappears, becoming cuneate. Leaf color    dark green above (Green Group 137-A), lighter below (Yellow-Green    Group 147-B). Upper surface of leaf smooth, underside slightly    hairy, especially on the veins. Hair easily loosened and can cause    eye/nasal irritation. Leaves slightly aromatic when crushed, not    considered unpleasant. Petiole 2-4″ long, depending on vigor and    location on the tree, slightly flattened perpendicular to the leaf    blade. Color variable: on young leaves, light green above and below    (Yellow-Green Group 152-D) changing to light brown above    (Grey-Orange Group 174-A) with age. The combination of large leaves,    long petioles and dense branch habit create a specimen tree that    gives an appearance of 100% foliation.-   Stipules: Typical of the species, ‘DRABROT’ produces stipules around    the nodes from which leaves emerge. Producing a stipular collar up    to 0.5″ wide and 1″ across, they are completely attached and    encircle the twig except are lobed and detached directly over the    petiole. Color Green Group 137-D. Stipules gradually dry and    disappear from twigs as they age.-   Twigs/buds: The conical vegetative buds are dark, (Greyed-Orange    Group 166-A) up to 0.25″ long×0.20″ wide, and only observed during    the dormant season after leaf drop has occurred. During the growing    season, buds are hidden and completely enclosed within the swollen,    hollow base of the leaf petiole. New growth (twigs) are circular to    oval in shape with faint longitudinal ribbing, Grey-Orange Group    165-A, darkening on larger (1″+ diameter), smooth branches    (Grey-Green Group 197-B to Greyed-Green Group-A).-   Flowers/fruit: As for the species, male and female flowers, not    showy, are borne in separate, drooping, ball-like heads. The female    heads of flowers develop into 1″ diameter globose heads of seeds.    The styles from the flowers extend from the ends of the seeds in the    fruits, but bristles, such as are present in the fruits of London    Planetree, are absent. Fruit color is Grey-Orange Group 164-C.    Flower buds have not been observed or described for the purpose of    this specification.

DESCRIPTION OF THE DRAWINGS

The accompanying color drawing, labeled FIG. 1, illustrates the overallappearance of ‘DRABROT’ showing the semi-weeping and contorted growthhabit, and the exfoliating bark patches, as exhibited on a 17-year olddormant, leaf-free specimen in a landscape application.

The accompanying color drawing, labeled FIG. 2, illustrates the overallappearance of ‘DRABROT’ in mid-summer, showing the dense habit and darkgreen, disease-free leaves, as exhibited on a 17-year old specimen in alandscape application.

The invention claimed is:
 1. A new and distinct variety of Platanusoccidentalis named ‘DRABROT’, substantially as described and illustratedherein.